Comment 16 for bug 938116

python-apt's documentation seems to indicate fairly clearly that one must create a new cache object after it's been externally modified, which makes some sense given that it's mmaped. A plausible source of trouble would be cached package objects that point into the old cache.

The traceback indicates (with a bit of imagination) that the crash is within self.store.clear(), which would make sense if update-manager were handling a signal on self.treeview_update in a way that involved references to the old cache. However, the workaround in bug 945536 has meant that the cursor-changed signal is a no-op for the duration of self.store.clear(). I wonder if this has caused this problem no longer to be visible in update-manager?